[GRASS-user] How to create an hull / area with v.in.ascii

[Philipp Steigenberger]

Hi there,
I have  cross-profiles of a river and want to create a terrainmodel.
To interpolate only there, where points are, I want to create a hull. 
v.hull doesn't work, cause - how to explain... - imagine, the river has 
the form of the letter 'S' with v.hull I get a form whisch is almost 
like a 'D'.

Therfore I extracte all the lines where I have the points of the 
right(r) /left(l) side of the cross-profile

I sort them like
cat   name
1         l 1
2         l 2
3         l 3
4         l 4
5         r 4
6         r 3
7         r 2
8         r 1

so it looks like:

1 4417744.050 5363469.320 461.10400 0.20000 P1(li)
2 4417723.140 5363269.800 461.83000 0.40000 P1(left)
3 4417716.890 5363068.970 461.40100 0.60000 P1(left)
4 4417705.220 5362867.590 461.93600 0.80000 P1(left)
354 4403074.030 5335808.330 559.44700 34.00000 P2(right)
355 4402974.470 5335628.060 559.60400 34.20000 P2(right)
356 4402876.360 5335452.300 560.11700 34.40000 P2(right)
357 4402779.380 5335277.370 561.11800 34.60000 P2(right)

I add
A 357 1 in the first line and
1 1         in the last line

Now I want to import this as an area:

cat wertach.asc | v.in.ascii --o output=wertach skip=1 -z z=4 cat=1 x=2 
y=3 colum='cat int, x double, y double, z double, name01 varchar(20), 
name02 varchar(20)' fs=' '

and get

Scanning input for column types...
Maximum input row length: 54
Maximum number of columns: 6
Minimum number of columns: 2
ERROR: y column number > minimum last column number
       (incorrect field separator?)

so I delete the last line and get

Scanning input for column types...
Maximum input row length: 54
Maximum number of columns: 6
Minimum number of columns: 6
WARNING: Column number 5 defined as string has double values
Importing points...
Populating table...
Building topology for vector map <wertach>...
357 primitives registered
Building areas:  100%
0 areas built
0 isles built
Attaching islands:
Attaching centroids:  100%
Topology was built
Number of nodes     :   357
Number of primitives:   357
Number of points    :   357
Number of lines     :   0
Number of boundaries:   0
Number of centroids :   0
Number of areas     :   0
Number of isles     :   0
v.in.ascii complete.

NO AREA :o(

If I try
B 357 1 for a boundary I get the same

Scanning input for column types...
Maximum input row length: 54
Maximum number of columns: 6
Minimum number of columns: 6
WARNING: Column number 5 defined as string has double values
Importing points...
Populating table...
Building topology for vector map <wertach>...
357 primitives registered
Building areas:  100%
0 areas built
0 isles built
Attaching islands:
Attaching centroids:  100%
Topology was built
Number of nodes     :   357
Number of primitives:   357
Number of points    :   357
Number of lines     :   0
Number of boundaries:   0
Number of centroids :   0
Number of areas     :   0
Number of isles     :   0
v.in.ascii complete.

NO BOUNDARY :o(

what went wrong? How to bulid an area? Do I need a centroid? How to get it?
Or do I only need x and y -values to create the area?

thanks for assistance

cheers
om shantih
Philipp